Weft stop motion for weaving machines

ABSTRACT

The present invention relates to a weft stop motion for weaving machines of the type in which weft is drawn from supply cones arranged outside the shed of a fabric being woven and a needle monitoring the weft thread so controlled that it is briefly trapped in or woven into the fabric when the weft thread is present, but is not held when the weft thread is absent, and serves then to initiate stopping of the weaving machine at each missing or incomplete pick of weft.

United States Patent [72] Inventor Oshr Bernath Umiken, AAr-gau, Switzerland [21 Appl. No. 792,484 [22] Filed 3:11.21, 1969 [45] Patented Aug. 31,1971 [73] Assignee Georg Fischer Ltd. Brugg, Switzerland [32] Priority Feb. 28, 1968 [3 3] Switzerland [31] 2 898/68 [54] WEFT STOP MOTION FOR WEAVING MACHINES 5 Claims, 7 Drawing Figs.

[52] US. Cl. 139/370 [50] Field of Search 1391370, 371

[56] References Cited UNITED STATES PATENTS 3,482,608 l2/ 1969 Riha et al 139/370 2,819,737 l/l958 Opletal 139/370 3,145,739 8/1964 Metzlerm. 139/370 3,260,283 7/1966 Svatyetal. 139/370 3,442,301 5/1969 Nydam 139/370 FOREIGN PATENTS 192,681 4/1967 U.S.S.R. 139/370 Primary Examiner-James Kee Chi Attomey-Rodney C. Southworth ABSTRACT: The present invention relates to a weft stop motion for weaving machines of the type in which weft is drawn from supply cones arranged outside the shed of a fabric being woven and a needle monitoring the weft thread so controlled that it is briefly trapped in or woven into the fabric when the weft thread is present, but is not held when the weft thread is absent, and serves then to initiate stopping of the weaving machine at each missing or incomplete pick of weft.

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INVENTUR. B 05164 BERN/i TH ATTORNEY wsr'r sror MOTION FOR WEAVING MACHINES BACKGROUND OF THE INVENTION Stop motions are known in the art (such as that in Swiss Pat. No. 430,612) which are mounted in an immobile part of the weaving machine and the needles of which penetrate into the warp threads between the reed and the beaten-up line or fell of the fabric. Such weft stop motions involve the disadvantage that the needles must additionally take part in a deflection of the weft at that point because, owing to the fabric contraction, the warp threads do not run normally from the reed to the temples. Particularly in finer fabrics, such deflections, owing to the needle tension or the mass forces of the needle holders, leave traces or imperfections which lower the value of the fabric.

It is an object of the present invention to provide a weft stop motion so mounted on the lay and reed of the weaving machine or to move therewith, and in which the mass of the moved parts is small so that the deflecting forces required for triggering the control signal are so small that no marks appear in the fabric produced and yet, the stopping of the weaving machine is certainly and effectively accomplished.

SUMMARY OF THE INVENTION According to the invention the said disadvantages are eliminated in that a holder firmly attached to the reed or otherwise fixed to move with the lay and reed, is provided with a contact member insulated relatively to it and at least one guide which may move substantially vertically in which a needle carrier subject to the action of a spring is actuated by a cam fixedly arranged on the weaving machine frame is adjustable together with a control roller or cam follower and the needle. Two embodiments of this invention are shownin the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section of a first embodiment of the weft stop motion according to this invention with the reed and the slay;

FIG. 2 is a plan view of the weft stop motion according to FIG. 1 with the cap or covering sheet removed;

FIG. 3 is a section of the weft stop motion according to FIGS. 1 and 2, the needle being held by a weft thread;

FIG. 4 is a diagram of the arrangement of the electrical switching members in the embodiment according to FIGS. 1-3;

FIG. 5 is a diagram of the interaction of switching pulses in the embodiment according to FIGS. 1-4;

FIG. 6 is a section of a further embodiment of the weft stop motion according to this invention together with the reed and the slay, and

FIG. 7 is a diagram of the interaction of the switching pulses in the embodiment according to FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a section of the first embodiment of the weft stop motion according to the invention. It shows a reed 5 and a slay comprising the section 1 with a race plate 2 and the reed being clamped by means of bolts 3 and an angle bracket 4. Guided by the reed 5 are the warp threads 6 which form the fabric 8 together with the weft threads 7, the said fabric beginning at the beating-up point or fell 9. Generally indicated are a temple roll 10 with a cover 11.

Clamped to the top of the reed 5 by means of screws 13 is a holder 12 which, according to FIG. 2, comprises two side members 14 with a generally vertical guide slot 15 in each. These slots 15 slidably hold a shaft 16 passing through a needle carrier 17 and also carrying a control roller 18. Fixed in a projection 19 of the needle carrier 17 by means of a screw 21 is a needle 20.

Centered in a holder 12 on a screw 22 is a compression pring 23 operative on an arm 24 of the needle carrier 17. The

compression spring 23 forces, via the needle carrier 17, the shaft 16 against a cap or covering sheet25 which prevents it 1 from being displaced beyond a predetermined limit and, on

I the other hand, forces the needle 20 against a contact stop 26 cable 29. Nut 28 also locks stop 26 in its adjusted position. Via

the needle 20 in circuit with the weaving machine, and an electrical conductor 29 connected to the contact stop 26, a completed circuit is obtained whenever the needle 20 is not under the action of extraneous forces, e.g. the pick of weft being beaten into the fabric or deenergization of the circuit as will hereinafter be described.

Owing to the movement of the slay section l in the direction of arrow 30, the weft thread 7, which has been inserted in the shed by insertion members (not shown) comes to rest against the reed 5 and comes up against the needle 20 as the latter moves downwards. The downward movement of the needle 20 is achieved by the engagement of the control roller or follower 18 with a cam 32 attached by means of screws 31, to the weaving machine by means of a cam support arm 33 not shown in its entirety. Arm 33 is fixed to some convenient fixed part of the weaving machine. The movement of the control roller 18 is transmitted to the needle 20 by the needle holder 17.

FIG. 3 is a section of the weft stop motion, the reed 5 and the slay as it moves away from the beating-up point in the direction of arrow 34; it also shows the needle 20 held between the fabric 8 and the last beaten-up weft thread 7 so that contact between the needle 20 and the contact stop 26 is interrupted. Thus the circuit cannot be completed. This position of the needle is referred to as one in which the needle is woven into the fabric. The return movement of the device in the direction of arrow 34 beyond the position shown in FIG. 3, enables the needle again to pull out upwardly from the fabric 8 and to assume the position according to FIG. 1.

FIG. 4 is a diagram of the arrangement of the electrical switching members, a pulse or time limiter 35, known per se in the art, and therefore not described in greater detail, is supplied, by way of example, with a l2-volt AC current via a switch 36 connected to operate with the starting means, a line 37 and a line 38 connected with the source of power at the weaving machine, the latter being grounded. Voltage is brought down to the 12 volts by a suitable transformer.

A disk 39 running in synchronism with the slay section 1, that is, one revolution for each beat-up motion, carries a slideably adjustable magnet 40 which actuates, by its magnetic field, a switch 41 and thus connects the two lines 42, 43 as the permanent magnet 40 moves past the switch 41 in its immediate vicinity. The switch 41 is preferrably a reed switch. The needle 20 is also grounded to the machine as at 38 and connects a line 44 which is the conductor 29 of FIGS. 1, 2 and 3, with the contact stop 26 when contact is established, that is, when the needle is not affected by a pick of weft. Connected to line 37 by a further line 45 is a relay 46. This relay 46 is the element which sets off the stop motion of the weaving machine as a result of the signal at the needle.

It is conceivable but not practical to try to trip the relay directly from the current through the needle. That current is preferably amplified by a signal amplifier circuit 53. In connection with the part of the circuit at 35 the current signalled by the needle contact at 26 at a time when switch 41 is closed assures a definite amplified signal for a time sufficient to affect relay 46 positively, but not longer than is desired. This part 35 of the circuit is, in effect, a condenser control for the relay. If the needle vibrates or chatters against contact 26, the signal is still effective.

The operation of the system for the embodiment shown in FIGS. 1-4 is illustrated in FIG. 5. The presence of a weft thread 7 is shown, according to FIGS. 3 and 4, by a short break of contact at the needle 20, ie the needle contact has a break period 48. This period starts before switch 41 is closed.

The passage of the permanent magnet 40 near the switch 41 produces a closed phase 50 on a theoretical O-line 49 of reed switch contact, the said period corresponding to the length of time the permanent magnet 40 affects switch 41. However, this is shortened by the pulse limiter 35 to a period 51 which is within an open period 49. The open period 48 on the theoretical O-line 47 of needle contact is that of the contact between needle and contact 26. Since with weft present, there is no contact at 20-26, the circuits 35 and 53 are ineffective or the amplifier is not conducting so that the relay is not energized to stop the weaving machine and the latter continues to operate.

However, if no weft thread 7 is located in front of the needle 20, the needle contact remains closed as indicated by the dotdash line 52 on needle contact line 47, FIG. 5. The pulse limiter or condenser circuit 35 thus becomes operative and the amplifier circuit 53 becomes conductive so as to energize the relay 46 which stops the machine by means (not shown) preferably the regular machine stop motion.

MODIFICATION FIG. 6 is a side view, partly in section, of the weft stop motion in another embodiment, the parts identical with those of the first embodiment being identified by the same reference numerals. Clamped to the reed 5 by means of bolts 113 is a holder 112 in which a guide channel 115 for a needle carrier 117 is provided and closed by a lid 114. The needle carrier 117 is under the action of a compression spring 123 held by a projection 124 of the lid 114 and which tends to raise the needle carrier 117. Located at the top of the needle carrier 117 on an axle l 16 is a control roller 118.

The needle carrier 117 is provided with an axle 119 to which a needle 120 is fixedly attached and which is forced against a needle 120 is fixedly attached and which is forced against a stop 122 on the needle carrier 117 by means of a torsion spring 121. One end of the torsion spring 121 is connected to the axle 119 and the other to the needle carrier 117. Not shown, is a conducting connection from ground (holder 1 12) to the torsion spring 121 so that the needle 120 possesses the same electrical potential as the machine.

Laterally of the needle carrier 117 slidable in the guide 115, an insulating member 127 is attached to the stationary holder 112. The insulating member 127 carries a resilient contact member 126 which is contacted by the swung-out needle 120, but is spaced from the needle 120 when it is idle. A line 129, such as a cable, leads from the contact member 126 to the electrical control and switching members.

The downward movement of the needle carrier 1 17 with the needle 120 is achieved when the control roller 118 engages with a cam 132 attached by means of bolts 131, to a holder 133 supported on a fixed part of the weaving machine.

The operation of the embodiment according to FIG. 6 is somewhat different in terms of the arrangement of the electrical controls, from that of the arrangement shown in FIGS. 4 and 5. FIG. 7 shows the essential differences. The establishment of contact between the contact member 126 and the needle 120 owing to its deflection, i.e. in the presence of a weft thread 7, results in a pulse 107 which is extended to a pulse 108 (indicated in dot-dash lines) by means of the timing or pulsing circuit.

Every weft insertion cycle produces a closure cycle 109 of switch 41, FIG. 4. As the pulse 108 overlaps the closed period 109, the latter cannot become operative to stop the weaving machine, which is the case in the presence of a weft thread.

However, if no pulse 108 is triggered owing to the absence of a weft thread, the closing period 109 becomes operative and stops the weaving machine.

It is advantageous to provide such an arrangement that the needle moves substantially parallel with the reed dents movement and at a distance of about 2 mm. therefrom. Owing to the direct and permanent arrangement of the needle on the reed 5 guiding the warp threads 6, the needle is not subject to any detrimental lateral forces due to ad 'acent warp threads during the movement of the reed 5 to the eating-up point and during its return. It does not abrade these warp threads.

Against the known needle weft stop motions, the design according to this invention possesses the advantage that the mass of the moving parts can be and is made very small and that a very small deflecting force is required to produce the control signals. Undesirable marks in the fabric produced are thus avoided, while the weaving machine is effectively stopped upon the absence of weft, especially at the very edge of a fabric woven in this type of machine.

This disclosure of preferred embodiments of the invention is to be interpreted as illustrative of forms the invention may take and other modifications will readily occur to those skilled in the art.

The invention is not to be restricted except by the scope of the appended claims wherein the novel features desired to be protected by Letters Patent are set forth:

1. A weft stop motion for a weaving machine of the type in which weft is drawn from a supply located outside the shed of a fabric being woven, said weaving machine having a slay and reed movable to beat each inserted pick of weft into the fabric as the latter is woven and which stop motion has a needle which is briefly inserted to be trapped in the fabric by a beaten-up pick of weft in the rhythm of the slay movement, but not so held when a pick of weft is not present at the needle, characterized by, a holder attached to the reed, a needle support including a pivot for the needle movable in a generally vertical direction as guided within said holder, said needle being pivoted on the support, a contact member on said holder forming a part of a stop motion circuit, biasing means to urge the needle to a definite position relatively to the contact member, and a cam supported on a fixed part of the weaving machine above the path of the reed engageable with a cam engaging part of the needle support for periodically moving it downwardly into the path of a pick of weft being beaten into the fabric.

2. A weft stop motion as defined in claim 1, wherein the contact member is insulated from the grounded circuit of the needle and the biasing means normally urges the needle into engagement with said contact member.

3. A weft stop motion as defined in claim 2, wherein the needle and contact member function within a circuit which is disabled to actuate the stop motion except when the reed i. moving to beat a pick of weft into the fabric.

4. A weft stop motion as defined in claim 3, wherein the circuit disabling means includes a magnetically controlled switch and a pulse limiter.

5. A weft stop motion as defined in claim 1, wherein the contact member is insulated from the grounded circuit of the needle and the biasing means normally urges the needle out of engagement with the contact member. 

1. A weft stop motion for a weaving machine of the type in which weft is drawn from a supply located outside the shed of a fabric being woven, said weaving machine having a slay and reed movable to beat each inserted pick of weft into the fabric as the latter is woven and which stop motion has a needle which is briefly inserted to be trapped in the fabric by a beaten-up pick of weft in the rhythm of the slay movement, but not so held when a pick of weft is not present at the needle, characterized by, a holder attached to the reed, a needle support including a pivot for the needle movable in a generally vertical direction as guided within said holder, said needle being pivoted on the support, a contact member on said holder forming a part of a stop motion circuit, biasing means to urge the needle to a definite position relatively to the contact member, and a cam supported on a fixed part of the weaving machine above the path of the reed engageable with a cam engaging part of the needle support for periodically moving it downwardly into the path of a pick of weft being beaten into the fabric.
 2. A weft stop motion as defined in claim 1, wherein the contact member is insulated from the grounded circuit of the needle and the biasing means normally urges the needle into engagement with said contact member.
 3. A weft stop motion as defined in claim 2, wherein the needle and contact member function within a circuit which is disabled to actuate the stop motion except when the reed is moving to beat a pick of weft into the fabric.
 4. A weft stop motion as defined in claim 3, wherein the circuit disabling means includes a magnetically controlled switch and a pulse limiter.
 5. A weft stop motion as defined in claim 1, wherein the contact member is insulated from the grounded circuit of the needle and the biasing means normally urges the needle out of engagement with the contact member. 